Among printing methods using an inkjet printer, a method is known in the art in which an UV curable ink is sprayed from an inkjet head and deposited on a printing medium, and then the ink droplets on the printing medium are cured and fixed to the printing medium by irradiating an ultraviolet light thereby printing an image on the printing medium. For example, Patent Document 1 discloses an image forming apparatus that has a compact structure and that accelerates curing of ink after the image is printed on a recording medium.
The UV curable ink has an advantage that it can be used on a non-absorbent printing medium. However, the UV curable ink has disadvantages that its characteristics change with changes in characteristics of the printing medium or changes in the environmental temperature. Moreover, spreading of ink on the printing medium continues until the UV curable ink reaches a stable area that is determined by a contact angle with the printing medium and a surface tension of the printing medium before the ink is cured and fixed by exposing to the ultraviolet light.